212657 has 4 divisors (see below), whose sum is σ = 220020. Its totient is φ = 205296.

The previous prime is 212651. The next prime is 212669. The reversal of 212657 is 756212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 39601 + 173056 = 199^2 + 416^2 .

It is a cyclic number.

It is not a de Polignac number, because 212657 - 2⁶ = 212593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (212651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3638 + ... + 3695.

It is an arithmetic number, because the mean of its divisors is an integer number (55005).

2²¹²⁶⁵⁷ is an apocalyptic number.

It is an amenable number.

212657 is a deficient number, since it is larger than the sum of its proper divisors (7363).

212657 is an equidigital number, since it uses as much as digits as its factorization.

212657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7362.

The product of its digits is 840, while the sum is 23.

The square root of 212657 is about 461.1474818320. The cubic root of 212657 is about 59.6888522029.

Adding to 212657 its reverse (756212), we get a palindrome (968869).

The spelling of 212657 in words is "two hundred twelve thousand, six hundred fifty-seven".